Electric switch



(No Model.)

Patented June 9,1891.

(No Model.) 2 Sheets-Sheet 2.

W. MITCHELL. ELECTRIC SWITCH.

No. 458,888. Patented June 9,1891.

cZZYfdS Z5:

d %%%Z WW UNITED STATES PATENT OFFICE.

IVILLIS MITCHELL, OF MALDEN, ASSIGNOR OF THREEFOURTHS TO EDlVARD JElVELL, OF BOSTON, AND LEX I L. PARSONS AND ARTHUR/B. SMITH, OF SAUGUS, MASSACHUSETTS.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 453,888, dated J une 9, 1891.

Application filed January 8,1891. .Serial No. 377,072. (No model.)

T all wh it may bridge, which turns on a standard or post F,

Be it known that I, WVILLIs MITCHELL, a raised centrally on said base, and is also mov-' citizen of the United States, residing at Malable up and down on the same. A spring G, den, in the county of Middlesex and State of surrounding said post above the said bridge,

Massachusetts, haveinvented certain new and forces the latter down on one or the otherpair 5 5 useful Improvements in Electric Switches; of said contact-plates or on the said cam and I do hereby declare the following to be a flanges, according to the position of the said full, clear, and exact description of the invenbridge. The spring at its upper end bears tion, such as will enable others skilled in the against the cross-bar H of a guide-frame, the

IQ art to which it appertains to make and use the said cross-bar being provided with an upward 6c same. tubular extension h, surrounding the said The principal object of this invention is to post, and is clamped to the latter by a screw provide electric switches with means for I, which enters a screw-tapped recess in the I promptly extinguishing the sparks or arcing head of said post, a washer i on said screw of the current caused by breaking the circuit. being located just above the top of said tubu- 6 It also provides improved means for increaslar extension, so as to prevent said cross-bar ing the strength of an electrical current by from rising.

combining two currents at Will in one circuit. From the cross-bar II guide-rods J extend These ends are effected by the devices heredownward through openings 6 in circuit-closinafter described and claimed. ing bridge E near the ends of the latter.

In the accompanying drawings, Figure 1 These rods compel the said bridge to turn represents a side elevation of a switch emwith the said cross-bar, the bridge sliding up bodying my invention. Fig. 2 represents a these guide-rods as its ends ride up the said similar view closing both circuits together. cam-flanges. The said rods are curved in 25 Fig. 3 represents a vertical section of Fig. 2, the direction of rotation to prevent the bridge takenlongitudinallythrough thebridge. Fig. from binding against them as its position- 4 represents a perspective view of the base thus changes, and also for an additional purand attachments. Fig. 5' represents an elepose, hereinafter stated. Ahandle K is provation at right angles to Figs. 1 and 2, the vided with. a transverse and also a vertical o circuit being broken; and Fig. (i representsa central opening 7., whereby it is sleeved on perspective view of the switch with the cassaid tubular extension h of guideframe crossing on. bar H. Wire fingers L are bent down from A designates the base of the switch, which the ends of this handle on opposite sides of is preferably of slate or other electricallysaid cross-bar, in order thatthe turning of 5 non-conducting material. On this base are the handle may turn the bridge also. The fastened two pairs of raised contact-plates B handle may be locked to the guide-frame by B and C-C,which have electrical connection means of screws Z, which extend in through below said base with circuit-wires b b and c openings 7; at the ends of said handle to and 0'. Each plate C or C is shorter than the through holes h in tubular extension h. A 40 neighboring plate B or B and has a groove casing M is provided for all the mechanism 0 c in its top. This groove is adapted to reexcept this handle and the upper end of said ceive a part of a bent spring D orD attached post. This casing isapplied when the switch to said neighboring contact-plate B or 13. is out of use, the said handle first being re- In the spaces between the two pairs of 0011- moved and afterward replaced outside of 45 tact-plates B C and B C ,Ilocate raised camsaid casing, as shown in Fig.7. Catches N 5 flanges D D, each having its lesser end to serve to hold the said casing in place on the ward one of the plates C or C and its larger said base. When the bridge E is turned by end toward the plate B or B of the opposite turning said handle from left to right, the pair. ends of the said bridge ride up the cam- 50 E designates a circuit closing metallic flanges D D and pass from the upper ends of the latter to the contact-plates B B. The circuit is then through wire I), contact-plate B, bridge E, contact-plate B, and wire I). On turning the bridge farther in the same direction the ends of it are transferred from contact-plates B B to contact-plates O 0, making the circuit through wire 0, contactplate 0, bridge E, contact-plate O, and wire 0. When the bent springs D and D are used, as shown, the pressure of spring G forces them into the grooves c of circuitplates 0 C, thus making electrical communication between plates 13 and O and also between plates B and O. In consequence both currents will be turned into the shorter of the'two circuits, thus increasing the strength of the current and the heating, lighting, or other desirable effect at will. WVhen the bridge is turned still farther in the same direction, it passes beyond the contact-plates C O, and is forced sharply downward by the spring G. WVhen the circuit is thus broken, a spark or are of light momentarily appears, the current having intensity enough to leap a slight interval. This undesirable phenomenon is common in switches. To do away with it I provide each end of said switch with an extinguisher 0, arranged on top and transversely thereof and having approximately the shape of a half-funnel longitudinally divided, the large end being presented forward in the direction of motion. The guide-rods J by their forward curvature guide the bridge in this direction, when the spring G is free to move it, as stated, and the sharp obliquely forward and downward motion thus caused produces a backward draft of air through the extinguishers, which, being concentrated at their small ends, blows out the sparks or areing.

' Having thus described my inventiomwhat I claim as new, and desire to secure by Letters Patent, is

1 In an electric switch, the combination of a movable circuit-closing bridge with hollow tapering extinguishers thereon and mechanism for directing the ends of said bridge obliquely forward and downward when contact is broken, for the purpose set forth.

2. In combination with a movable bridge and forward curved guide-rods for directing the motion of the same, a spring bearing on said bridge, contact-plates to make electrical connection therewith, and hollow tapering spark-extinguishers carried by the ends of said bridge, substantially as set forth.

3. In combination with a circuit-closing bridge and a spring bearing thereon, two pairs of contact-plates and their electrical connections, and electrical conductors attached to the contact-plates of one pair and arranged to be forced by said spring and bridge against the contact-plates of the other pair, thus uniting both currents in one circuit, substantially as set forth.

4. In combination with a circuit-closing bridge and a spring bearing thereon, a pair of contact-plates B B, a pair of springs D D attached thereto, a second pair of contactplates 0 C, having grooves c in their tops, adapted to receive the said springs, and the circuit-wires b l) c c, the springs D D being arranged to be forced into the grooves c by the pressure of the bridge and its spring, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

IVILLIS MITCHELL.

Witnesses:

W. P. CUTLER, ROBERT W. SCOTT. 

